It seems like there’s a “best” supplement for everything these days—beautifully packaged capsules, powders, and tinctures claiming to boost hair growth, ease digestive distress, plump your skin, prevent migraines, enhance sleep , support immunity, rev energy, and more.
This promise of improved health—sans prescription medication—in such an easily accessible format is incredibly enticing, especially in a world where many doctors are quick to jump to prescription drugs before exploring natural protocols or lifestyle changes . This (along with plenty of slick marketing) may be why Americans are increasingly turning to supplements , with approximately 75 percent of U.S. adults taking some type of supplement on a regular basis.
So, what’s the problem? While it’s true that the right supplements in the right situations can be total game-changers, there are two big issues with supplements today: Lack of regulation, which can mean subpar quality and contamination, and lack of personalized guidance, which can result in even high-quality supplements having unintended consequences and side effects . (Or, not working for what you intended them to.)
“Just because a supplement is available without a prescription doesn’t mean it can’t potentially cause dangerous side effects,” says Ivy Carson , a nurse practitioner at Parsley Health . Below, we explain why it’s important to be really picky when choosing a supplement and when deciding what supplements to take in the first place—plus, some expert-approved tricks on how to see through the hype and find high-quality supplements worth taking.
“Over-the-counter supplements are not regulated in the same way that prescription medications are,” says Carson. While the Food & Drug Administration (FDA) does maintain a set of quality and safety guidelines that supplements are supposed to meet—current good manufacturing practices (cGMP) —“there’s not much oversight and enforcement of these,” she says.
In fact, there’s basically no oversight and enforcement. While the FDA will investigate a supplement after a complaint is made about potential safety violations, they do not play any role in enforcing cGMP guidelines before a supplement hits the market—they leave it up to the supplement companies themselves. According to the FDA , “Manufacturers and distributors of dietary supplements and dietary ingredients…are responsible for evaluating the safety and labeling of their products before marketing to ensure that they meet all the requirements.”
All of which is to say: The barrier of entry into the marketplace for new supplements is very low, and it’s easy to see how lack of official oversight may lead to the problems mentioned below.
The lack of regulation and oversight means that supplements could contain “unlisted additives, fillers, or potential allergens,” says Carson, which might include things like artificial colors and preservatives. Some of the ingredients in supplements may not be properly tested for environmental toxins either—“the heavy metals lead and mercury would be high on the list of things to be concerned about there,” says Carson.
Lead and mercury are found in higher levels in the soil in certain parts of the world, such as India, explains Carson, so supplement ingredients sourced from these areas may contribute to this contamination if not properly tested. If these end up in supplements, it’s typically by mistake, but some potentially harmful ingredients are actually added on purpose.
In fact, a 2018 study found that several supplements marketed for weight loss, sexual enhancement, and muscle growth contained active pharmaceuticals with the likelihood to cause serious adverse health effects due to accidental misuse, overuse, or potential interactions with other medications.
If current good manufacturing practices (cGMP) aren’t being followed, different batches of the same supplement may be inconsistent—meaning, they could contain different percentages of key active ingredients, which affect the supplement’s efficacy. “So if people stick with the same supplement and brand, but the next bottle doesn’t work as well, that may be what’s happening,” says Carson. And keep in mind, this can go either way: The recommended dose could contain more or less of certain ingredients than it should, which could trigger unintended side effects.
Despite the fact that supplement labels list one recommended dose for pretty much everyone, the truth is, one size does not fit all when it comes to supplements . “If you consider a 90-pound woman and a 300-pound man, they’re going to have different needs,” says Carson. “But the dose on the label is not reflective of that.”
Carson adds that there is often a difference between the minimum amount of a nutrient someone needs to prevent a deficiency (which is often reflected in the recommended daily intake) and the amount someone might need to function optimally. The amount someone needs for optimal health is highly individual and may depend on their diet, health status, genetics, and more. So if you’re taking the dose recommended on the label, it may be completely wrong for your specific needs (and as a result, a big waste of money).
Even the most health-conscious people end up with quite a few pills and powders in their daily rotation . The problem: Even if they’re marketed as having distinct benefits (hair growth vs mood-booster vs sleep-enhancer vs inflammation -fighter), they could have a variety of overlapping ingredients. And even if each supplement contains a safe dosage of its respective ingredients, the cumulative effect of taking all of these on a regular basis could push you into dangerous nutrient-overdose territory.
“A common misconception is that if some is good, more is better,” says Carson. While some nutrients are relatively safe even at higher doses (think: water-soluble vitamins such as vitamin C and B vitamins), some can have serious or unpleasant side effects. “Iron and fat-soluble vitamins—vitamins A, D, E, and K —can build up in your system and become toxic.”
Per the National Institutes of Health Office of Dietary Supplements , too much vitamin A can cause headaches and liver damage, weaken bones, and cause birth defects; and too much iron causes nausea and vomiting and may damage the liver and other organs. Getting way too much of one nutrient could also throw off your levels of other nutrients. For example, people loading up on zinc for an extended period of time in an attempt to boost immunity during the pandemic may have unintentionally put themselves at risk of a copper deficiency , because zinc and copper compete for the same binding sites in the body, explains Carson.
The average person isn’t a doctor, herbalist, or health coach with a comprehensive understanding of vitamins, minerals, and herbs. Meaning, you’re bound to make mistakes regarding what supplements you take and how you take them. This is yet another reason why self-treating with supplements—without professional input—can be so problematic. In addition to what’s already been listed above, Carson shares some common mistakes people tend to make with supplements:
Supplements can be a game-changer for your health, and Carson has seen responsible supplement use lead to major improvements in patients with digestive issues, fatigue , brain fog , anxiety , migraines, problems sleeping, and low energy. And, while they’re never a replacement for a healthy diet, Carson says that supplements can be a powerful tool in alleviating nutrient deficiencies that may be a result of digestive issues, or filling the gaps in a mostly healthy diet.
But how do you determine what you truly need (and what you don’t)? Seek out a medical professional who is well versed in supplements and herbs. They can take a comprehensive medical history, and you can bring up any symptoms you’d like to address. From there, appropriate lab testing (e.g. standard blood work; more in-depth vitamin, mineral, amino acid, and fatty acid level testing ; and even stool testing) can be done to help your clinician determine what supplements you need and what dose is optimal for you. Then, after a period of time, you can perform these labs again to adjust your dose as needed.
Knowing what supplement (and dose) you need is only half the battle. As discussed earlier, supplement quality is all over the place due to a lack of enforced regulatory standards. But great supplements do exist —you just have to know what to look for.
If a supplement company eludes that it can transform your health, it’s usually a red flag. That’s why you should look past the splashy claims on the front of the label or the company’s website and hone in on the key ingredients instead. A supplement’s ingredient list, and its concentration of certain ingredients, will provide a better indicator of how well the product may work and if it contains anything potentially dangerous. Not sure what forms and concentrations of a nutrient you should be looking for? Wondering if something you can’t pronounce is safe, or a potentially dangerous or unnecessary additive that could interfere with absorption? When in doubt, run it by a medical professional.
Because the FDA entrusts supplement companies to do their own testing for safety, consistency, and potency, there’s a lot of room for error and cutting corners. That’s why seeking out a supplement brand with third-party testing should be the bare minimum (look for a stamp of approval from companies like NSF, USP, or Consumer Lab)—while this doesn’t guarantee safety and effectiveness, it does mean that a neutral party has verified that a supplement was properly manufactured, contains the ingredients listed on the label, and does not contain harmful levels of contaminants such as heavy metals.
Even after you’ve eliminated all supplements that aren’t third-party tested, there are still a dizzying array of options. Work with a healthcare provider to determine what supplements are safe, pure, and have yielded positive results among patients. “At this stage in my practice, I know the brands that I trust and how they test their ingredients,” says Carson.
Many of the brands that are go-tos for Carson are considered pharmaceutical grade supplements , like Parsley Health’s line of supplements . This means they are only available through reputable medical practices and must meet a more stringent set of criteria than OTC supplements: For example, they must be absorbed by the body within 45 minutes; they must exceed 99% purity of the listed active ingredient and contain no fillers, dyes, and binders; and the raw ingredients used in these supplements must be tested before production.
Supplements can be an important part of an overall health plan, but working with a medical professional who can help you determine the types of supplements you need (via appropriate testing) and steer you toward the most reputable brands is your best strategy.
Stephanie Eckelkamp is a writer and certified health coach based in Allentown, PA. She received her B.S. in journalism from Syracuse University with a minor in nutrition. Her work has appeared in Martha Stewart Living, mindbodygreen, Greatist, Women's Health, Men's Health, Prevention, and Good Housekeeping. When she's not writing or nerding out on the latest health news, she's most likely on a walk with her pup Lucy Goose or trying to convince her boyfriend to eat more broccoli.